%I A056431
%S A056431 1,2,3,7,7,33,29,149,245,1230,1665,15973,18199,134482,376433,1415209,
%T A056431 2634597,26534612,33499359,287002711,727425501,3332040944,5794658931,
%U A056431 61120855045,93825569009,601444738252
%N A056431 Step cyclic shifted sequence structures using a maximum of four different 
               symbols.
%C A056431 See A056371 for an explanation of step shifts. Under step cyclic shifts, 
               abcde, bdace, bcdea, cdeab and daceb etc. are equivalent. Permuting 
               the symbols will not change the structure.
%D A056431 M. R. Nester (1999). Mathematical investigations of some plant interaction 
               designs. PhD Thesis. University of Queensland, Brisbane, Australia.
%F A056431 Use de Bruijn's generalization of Polya's enumeration theorem as discussed 
               in reference.
%Y A056431 Cf. A056412.
%Y A056431 Sequence in context: A104138 A083809 A092967 this_sequence A011027 A100072 
               A089008
%Y A056431 Adjacent sequences: A056428 A056429 A056430 this_sequence A056432 A056433 
               A056434
%K A056431 nonn
%O A056431 1,2
%A A056431 Marks R. Nester (nesterm(AT)dpi.qld.gov.au)